We usually perform geomorphic analysis on a particular river channel profile by using ASTER DEM with 30m resolution (or any other type of DEM). How we can define a particular knickpoint as major or minor. Is there any rules to define them quantitatively i.e 10m vertical drop/100m or 10/500m etc ? any idea ? I appreciate your time and prompt response. Thanks
Dear Muhammad,
I do not know any rules for such analysis. But it is definetly that such classification should strongly depend on DEM's resolution. For example, if we use the 3" SRTM DEM with ~90 m point spacing it is useless to measure verical drop / 100 m. I Think that definition of "major" and "minor" should depend on this parameter and on the scale and detailness of the research.
Thank Sir,
Actually I am working on the revision of MS on knickpoints and mass wasting processes along Indus River. I used ASTER GDEM v2 30m resolution data to extract longitudinal profile (by selecting 250m smoothing window). One of the reviewer has asked me to define the major and minor knickpoints quantitatively. i was looking through the literature for this query. Regards
Dear Muhammad,
I would suggest you to analyse the size-frequence distribution of the knickpoints that you have identified in the study region. Check - if it would be normal or log-normal or, may be, bimodal? And make your own division.
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